Regulating capacity and managing services of computing environments and systems that include a database

ABSTRACT

Capacity of a database system and/or a computing system that includes a database can be effectively changed from a current computing capacity to another computing capacity. This can be achieved by causing usage capacity of at least one of resource to be changed when the database is active. By way of example, capacity of a database system can be regulated by delaying the execution of the database work based on a target capacity. As a result, database work can take relatively longer to complete when the capacity of a database is effectively regulated to be below its full capacity. In effect, a portion of available capacity (excess capacity) can be made inaccessible to the database. However, excess capacity can be used to manage various services of the database in accordance with one or more service criteria (e.g., Service Level Goals or Agreements).

BACKGROUND

The term database can refer to a collection of data and/or data structures typically stored in a digital form. Data can be stored in a database for various reasons and to serve various entities or “users.” Generally, data stored in the database can be used by the database users. A user of a database can, for example, be a person, a database administrator, a computer application designed to interact with a database, etc. A very simple database or database system can, for example, be provided on a Personal Computer (PC) by storing data on a Hard Disk (e.g., contact information) and executing a computer program that allows access to the data. The executable computer program can be referred to as a database program or a database management program. The executable computer program can, for example, retrieve and display data (e.g., a list of names with their phone numbers) based on a request submitted by a person (e.g., show me the phone numbers of all my friends in Ohio).

Generally, database systems are much more complex than the example noted above. In addition, databases have been evolved over the years and some databases that are for various business and organizations (e.g., banks, retail stores, governmental agencies, universities) in use today can be very complex and support several users simultaneously by providing very complex queries (e.g., give me the name of all customers under the age of thirty five (35) in Ohio that have bought all items in a list of items in the past month in Ohio and also have bought ticket for a baseball game in San Diego and purchased a baseball in the past 10 years).

Typically, a Database Management System (DBMS) is provided for relatively large and/or complex database. As known in the art, a DBMS can effectively manage the database or data stored in a database, and serve as an interface for the users of the database. A DBMS can be provided as an executable computer program (or software) product as also known in the art.

It should also be noted that a database can be organized in accordance with a Data Model. Notable Data Models include a Relational Model, an Entity-relationship model, and an Object Model. The design and maintenance of a complex database can require highly specialized knowledge and skills by database application programmers, DBMS developers/programmers, database administrators (DBAs), etc. To assist in design and maintenance of a complex database, various tools can be provided, either as part of the DBMS or as free-standing (stand-alone) software products. These tools can include specialized Database languages (e.g., Data Description Languages, Data Manipulation Languages, Query Languages). Database languages can be specific to one data model or to one DBMS type. One widely supported language is Structured Query Language (SQL) developed, by in large, for Relational Model and can combine the roles of Data Description Language, Data Manipulation language, and a Query Language.

Today, databases have become prevalent in virtually all aspects of business and personal life. Moreover, database use is likely to continue to grow even more rapidly and widely across all aspects of commerce. Generally, databases and DBMS that manage them can be very large and extremely complex partly in order to support an ever increasing need to store data and analyze data. Typically, larger databases are used by larger organizations. Larger databases are supported by a relatively large amount of capacity, including computing capacity (e.g., processor and memory) to allow them to perform many tasks and/or complex tasks effectively at the same time (or in parallel). On the other hand, smaller databases systems are also available today and can be used by smaller organizations. In contrast to larger databases, smaller databases can operate with less capacity. In either case, however, there is a need for a flexible database environment that can adjust better to the needs of it users and also allow the capacity of the database to change as the need of its users change.

In view of the foregoing, techniques for controlling the capacity for computing environments or systems that include a database are needed.

SUMMARY

Broadly speaking, the invention relates to computing systems and computing environments. More particularly, the invention pertains to techniques for controlling the capacity of database environments and systems that include and/or support a database and/or a database system.

In accordance with one aspect of the invention, the capacity of a database system and/or a computing system that includes a database can be effectively changed from a current computing capacity to another computing capacity, different than the current capacity. It will be appreciated that this can be achieved by causing usage capacity of at least one of the resources to be changed from a current usage capacity to another usage capacity different than the current usage capacity. It will also be appreciated that the capacity of database system and/or a computing system that includes a database can be effectively changed when the database is active, operational and/or processing data or requests, in a dynamic manner, at run time.

The invention can be implemented in numerous ways, including, for example, a method, an apparatus, a computer readable medium, a database system, and a computing system (e.g., a computing device). A computer readable medium can, for example, include at least executable computer program code stored in a tangible form. Several embodiments of the invention are discussed below.

In accordance with one embodiment of the invention, a database or database system can be operable to control or regulate its capacity and/or the capacity of its computing environment by effectively controlling or regulating access (e.g., access by database work) to one or more resources including, for example, access to one or more processors (or execution time), access to I/O operations (e.g., reading and writing to the database). By way of example, capacity of a database system can be regulated by delaying the execution of the database work based on a target capacity. As a result, database work can take relatively longer to complete when the capacity is regulated to be below its full capacity. For example, if a particular database work would takes one (1) unit of time to complete at full capacity, the same database work could take more than one (1) unit of time, possibly (2) units of time, at half capacity, and so on.

Various techniques can be used to regulate capacity. In accordance with one embodiment, a task scheduler can effectively regulate access to resources by delaying database work done by a database system based on a target or desired capacity for the database system. As another example, one or more the clocks for one or more processors provided in one or more database nodes of a database system can be set based on a target or desired capacity in accordance with another embodiment of the invention.

In accordance with another aspect of the invention, it can be determined based on one more criteria and/or events whether to use excess capacity available to a database system and excess capacity can be used accordingly. By way of example, it can be determined to use excess capacity to meet a service level goal and/or service level agreement. In one embodiment, a database system that regulates capacity can allow excess capacity to be used for various purposes. The database system can be operable to allow only specific tasks or activities (e.g., a database task with a Service Level Agreement) to use excess capacity.

In accordance with yet another aspect of the invention, capacity and/or excess capacity provided and/or used by a database and/or database system can be measured and/or accounted, thereby allowing various utility models, including, for example, Capacity on demand (COD) to be provided for various applications, for example, billing customer of database systems based on usage and/or excess usage. In one embodiment, a database system is operable to regulate capacity is also operable to measure excess capacity provided, for example, to meet a service level agreement.

Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

FIG. 1A depicts a computing environment including a capacity management system provided for a database (or a database system) in accordance with one embodiment of the invention.

FIG. 1B depicts a multi-node database system, including a computing capacity management system in accordance with one embodiment of the invention.

FIG. 1C depicts a method for controlling capacity of a database system in accordance with one embodiment of the invention.

FIG. 2 depicts a method for processing data by a database (or database system) in accordance with one embodiment of the invention.

FIG. 3 depicts a method for controlling the capacity of a database (or a database system) in accordance with another embodiment of the invention.

FIG. 4A depicts a capacity management system for a database in accordance with another embodiment of the invention.

FIG. 4B depicts a method for controlling the capacity of a database in accordance with yet another embodiment of the invention.

FIG. 4C depicts a method for processing one or more database tasks or activities in accordance with one embodiment of the invention.

FIG. 5 depicts a “closed-loop” capacity and workload management system 500 in accordance with one embodiment of the invention.

FIG. 6 depicts in greater detail the regulator in accordance with one embodiment of the invention.

FIG. 7 depicts in greater detail query (delay) manager in accordance with one embodiment of the invention.

FIG. 8 depicts in greater detail an exception monitoring in accordance with one embodiment of the invention.

FIG. 9A depicts in greater detail an exception monitor as a part of a regulator in accordance with one embodiment of the invention.

FIG. 9B depicts a subsystem condition detector and adjuster (SSCDA) and a system condition detector and adjuster (SCDA) in accordance with one embodiment of the invention.

FIG. 9C depicts an arrangement for handling inputs and outputs to and from a SCDA in accordance with one embodiment of the invention.

FIG. 10 depicts a database node of a database system or database management system (DBMS) in accordance with one embodiment of the invention.

FIG. 11 depicts a Parsing Engine (PE) in accordance with one embodiment of the invention.

FIG. 12 depicts a Parser in accordance with one embodiment of the invention.

FIG. 13 depicts a computing environment in accordance with one embodiment of the invention.

FIG. 14A depicts a method for managing services of a database in accordance with one embodiment of the invention.

FIG. 14B depicts a method for managing services of a database in accordance with another embodiment of the invention.

FIG. 15 depicts an exemplary priority management scheme in accordance with one embodiment of the invention.

DETAILED DESCRIPTION

As noted in the background section, databases have become prevalent in virtually all aspects of business and personal life. Moreover, database use is likely to continue to grow even more rapidly and widely across all aspects of commerce. Generally, databases and DBMS that manage them can be very large and extremely complex partly in order to support an ever increasing need to store data and analyze data. Typically, larger databases are used by larger organizations. Larger databases are supported by a relatively large amount of capacity, including computing capacity (e.g., processor and memory) to allow them to perform many tasks and/or complex tasks effectively at the same time (or in parallel). On the other hand, smaller databases systems are also available today and can be used by smaller organizations. In contrast to larger databases, smaller databases can operate with less capacity. In either case, however, there is a need for a flexible database environment that can adjust better to the needs of it users and also allow the capacity of the database to change as the need of its users change.

Accordingly, techniques for controlling the capacity for computing environments or systems that include a database are needed. In particular, controlling the capacity of database systems would be very useful, especially given the prevalence of the database in various aspects of business and life in the world today.

Furthermore, it is likely that the use of databases will still continue to grow rapidly to serve an even wider range of entities with widely differing needs and requirements. Hence, it would be useful to control the capacity of computing environments or systems that include a database. In particular, it would be very useful to allow the capacity of a database to change as desired or needed. In other words, it would be very useful to provide a database system that can change its capacity or ability to perform various database related tasks, activities, etc. (or “database work”). For example, the ability to rapidly upgrade hardware resources (e.g., number of database nodes and their corresponding processors) in what may be budget-friendly increments to customers or purchasers of a database is highly desirable and useful. It would also be very useful to provide capacity to users, customers and/or purchasers of database as desired or needed (e.g., providing Capacity on Demand (COD)).

In accordance with one aspect of the invention, the capacity of a database system and/or a computing system that includes a database can be effectively changed from a current computing capacity to another computing capacity, different than the current capacity. It will be appreciated that this can be achieved by causing usage capacity of at least one of the resources to be changed from a current usage capacity to another usage capacity different than the current usage capacity.

It will also be appreciated that the capacity of database system and/or a computing system that includes a database can be effectively changed when the data base is active, operational and/or processing data or requests, in a dynamic manner, at run time. In accordance with one embodiment of the invention, a database or database system can be operable to control or regulate its capacity and/or the capacity of its computing environment by effectively controlling or regulating access (e.g., access by database work) to one or more resources including, for example, access to one or more processors (or execution time), access to I/O operations (e.g., reading and writing to the database). By way of example, capacity of a database system can be regulated by delaying the execution of the database work based on a target capacity. As a result, database work can take relatively longer to complete when the capacity is regulated to be below its full capacity. For example, if a particular database work would takes one (1) unit of time to complete at full capacity, the same database work could take more than one (1) unit of time, possibly (2) units of time, at half capacity, and so on.

Various techniques can be used to regulate capacity. In accordance with one embodiment, a task scheduler can effectively regulate access to resources by delaying database work done by a database system based on a target or desired capacity for the database system. As another example, one or more the clocks for one or more processors provided in one or more database nodes of a database system can be set based on a target or desired capacity in accordance with another embodiment of the invention.

In accordance with another aspect of the invention, it can be determined based on one more criteria and/or events whether to use excess capacity available to a database system and excess capacity can be used accordingly. By way of example, it can be determined to use excess capacity to meet a service level goal and/or service level agreement. In one embodiment, a database system that regulates capacity can allow excess capacity to be used for various purposes. The database system can be operable to allow only specific tasks or activities (e.g., a database task with a Service

Level Agreement) to use excess capacity.

In accordance with yet another aspect of the invention, capacity and/or excess capacity provided and/or used by a database and/or database system can be measured and/or accounted, thereby allowing various utility models, including, for example, Capacity on demand (COD) to be provided for various applications, for example, billing customer of database systems based on usage and/or excess usage. In one embodiment, a database system is operable to regulate capacity is also operable to measure excess capacity provided, for example, to meet a service level agreement.

Other aspects of the invention include a “closed-loop” capacity management architecture.

Embodiments of these aspects of the invention are also discussed below with reference to FIGS. 1A-15. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments.

FIG. 1A depicts a computing environment 100 including a capacity management system 101 provided for a database (or a database system) 102 in accordance with one embodiment of the invention. Although not shown in FIG. 1A, it should be noted that the database or database system 102 can also include a Data Base Management System (DBMS). Those skilled in the art will readily appreciate that the capacity management system 101 can be provided by hardware and/or software. For example, the capacity management system 101 can be provided as executable code stored on a computer storage medium (not shown) that can be read and executed by one or more processors (not shown).

As will be described in more detail below, the capacity management system 101 can control the capacity of the database 102. As such, the capacity management system 101 can, for example, be operable to change, vary, and/or maintain the capacity of the database 102 in a controlled manner. Although depicted as a component separate from the database 102, it should be noted that the capacity management system 101 may partially or entirely be implemented as a part of the database (or database system) 102 as will be appreciated and readily understood by those skilled in the art. In particular, it will be appreciated that the capacity management system 101 can be provided at least in part in or by a DBMS (not shown in FIG. 1A).

Referring to FIG. 1A, generally, capacity management system 101 can use one or more resources 104 in order to process data or requests associated with the database 102. The resources 104 can, for example include processors, memory, access to various services and functions (e.g., Input and Output (I/O) operations, including reading and writing of the data to and from the database 102).

As will be appreciated by those skilled in the art, the resources 104 may be a part of the database 102 or be a part of a larger computing environment or system, namely the computing environment 100. Also, the database 102 can include one or more database nodes, each including one or more processors operable to process data which is typically stored in a computer readable storage medium (e.g., a hard disk). It should be noted that the processor(s) and the computer readable storage medium of a database node may be a part of the resources 104.

The database 102 may, for example, be a conventional database operable to perform conventional functions. As such, the database 102 can be a database system with multiple database nodes. In other words, the database 102 can include multiple database nodes (Node1 to Node N) where a database node (Node I) can access one or more resources 104 (e.g., processors, volatile memory, persistent memory, persistent storage, Input/output (I/O) operations, communication or networking capabilities, Operating System (OS)). As a multi-node database, each one of the database nodes 1-N can operate and process data independently but in a coordinated manner, which may allow the database nodes to communicate with a central entity (e.g., a database managing component) and/or directly or indirectly with each other. A multi-node database system is described further below with reference to FIG. 1B in accordance with one embodiment of the invention.

However, referring back to FIG. 1A, generally, the database 102 or one or more database nodes of the database 102 can access one or more resources 104 in the computing environment 100 to perform one or more tasks and/or to process data. As known in the art, generally, a resource 104 can be a physical or virtual component and may be used to perform or to facilitate performing a task or a computing task (e.g., processing or manipulating data, reading or writing data, communicating data to an internal or external component). As such, a resource 104 may be a physical resource. For example, one or more internal physical components of the database 102, or one or more devices connected to the database 102 can be computing resource 104 in the computing environment 100.

A resource 104 may also be a virtual resource. For example, various files, network connections and memory areas can be virtual resources 104 that may be available to the database 102. As such, a resource 104 can, for example, include resources or computing resources often used to perform computing tasks (e.g., one or more general purpose or specialized processors, memory, access to I/O operations to read and write data) as well as various other resources (e.g., hard disk space, Random Access Memory (RAM), cache memory, and virtual memory, network throughput, electrical power, external devices, external devices).

Generally, a database or database system 102 can be provided by or as a system or computing system with an associated level of capacity, including computing capacity which can be representative of its potential to perform tasks. By way of example, for a relatively simple Personal Computer (PC), the computing capacity of the PC can be closely related to the clock cycle of its processor or as more commonly known its processing power or speed (e.g., one (1) Giga Hertz (GHZ)). However, more accurately, the computing capacity of a computing system can be closely related to all of the resources available to the computing system, including but not limited to its processor(s), memory, ability to perform I/O functions, its networking capabilities, storage space). As such, the computing capacity of the database 102 can be closely related to virtually all of the resources 104 available to it in the computing environment 100. It should also be noted that capacity of the database 102 does not necessary reflect its actual or current level of usage. Rather, the capacity of the database 102 is generally related to a maximum level of usage that can be accommodated by the resources 104.

To further elaborate, consider when that database 102 is provided as a computing system. In that case, when the capacity of the computing system is at full capacity or one hundred (100) percent, the computing system can be operable up to its maximum potential capacity. This does not, however, mean that the computing system has to operate or ever reach its capacity or maximum potential. As such, a computing system may, for example, be operating at seventy five (75) percent capacity even though it is operable at full capacity or one hundred (100) percent capacity when it is determined to reduce its capacity from full capacity to one half (or 50 percent). However, in the example, when the capacity is reduced from full capacity to half or fifty (50) percent, the computing system can no longer operate at 75% percent of its full capacity (i.e., the level it was operating before its capacity was reduced from).

To further elaborate, FIG. 1A depicts the controlled capacity of the database 102 and the actual usage of the capacity (i.e., actual usage of resources 104 by the database system 102) over time. As such, the capacity of the database 102 can be a cap placed on the extent of usage of the resources 104. In other words, the capacity of the computing environment 100 and/or database 102 can be controlled by controlling the extent in which the resources 104 are made available in accordance with one aspect of the invention. Moreover, it will be appreciated that the capacity management system 101 can control the capacity of the database 102 so as to change or vary the capacity over time in a controlled manner in accordance with another aspect of the invention. This means that the capacity management system 101 can effectively change the capacity of the database system 102 from a first capacity (C1) at a time T1 to a second capacity (C2) at time T2, which is different than the first capacity (C1). In other words, the capacity of the database system can be changed or varied at runtime or execution time in a dynamic manner.

As depicted in FIG. 1A, the computing capacity of the computing environment 100 and/or database system 102 can be varied over time. Moreover, the capacity management system 101 can achieve this variation of the computing capacity in a controlled manner, where the current computing capacity may be increased or decreased as desired and/or needed. This means that the capacity of the database 102 and/or computing environment 100 can be controlled on demand to provide Capacity On-Demand, or Capacity on Demand (COD).

As will be described in greater detail, the capacity management system 101 can use various techniques in order to effectively change the capacity of the database 102. By way of example, the capacity management system 101 can be operable to change the effective processing speed (or maximum processing speed) of one or more processors provided as, or among, the resources 104. In addition, or alternatively, the capacity management system 101 can, for example, be operable to change the effective rate in which the processors operate (e.g., by skipping one or more clock cycles). As another example, access or execution time of one or more processors provided as or among the resources 104, as well as other various other resources 104 (e.g., access to I/O operations) can be delayed. In addition, the time, rate and/or duration of access to a resource 104 can be controlled to effectively monitor and limit the extent of access to the resource 104. Techniques for changing the capacity of the database system 102 are discussed in greater detail below.

By in large, the computing capacity of a computing system, which may be more directly related to its ability (e.g., performing tasks, processing data) can be a good representative of its overall or general capacity. As such, rather than controlling all the resources 104 representative of a general capacity which may include resources less directly related to performing computing tasks (e.g., hard disk capacity, power resource, network capability), controlling the computing capacity by controlling the resources that are more directly related to performing tasks and processing data can be sufficient, especially for database systems that primarily function to process data and requests pertaining to data stored in a database. Accordingly, techniques for controlling the computing capacity of database system are further discussed below in greater detail. The techniques are especially suited for computing systems that primarily function to perform computing tasks (e.g., database systems, computing systems that primarily function to process data and/or perform computing tasks).

As noted above, the database or database system 102 (depicted in FIG. 1A) can, for example, be a multi-node database system. Moreover, it will be appreciated that a capacity management system 101 can be provided to control the capacity of a multi-node database system 102. In fact, such a capacity management system can be provided as a part of a multi-node database system 102.

To further elaborate, FIG. 1B depicts a multi-node database system 120, including a computing capacity management system 121 in accordance with one embodiment of the invention. It will be appreciated that the computing capacity management system 121 can be operable to change the computing capacity of multiple database nodes (Nodes 1-N) of the database system 120 at execution time in a controlled and dynamic manner. This means that the computing capacity management system 121 can effectively control the computing capacity of the multi-node database system 120 by effectively controlling the computing capacity of one or more (or all) of the database nodes 1-N when data is being processed by one or more database nodes 1-N of the multi-node database system (e.g., when database queries are being processed). In other words, capacity management system 121 can effectively control the extent of access to resources 104 by one or more (or all) of the database nodes 1-N of the multi-node database system 120.

It should be noted that the computing capacity management system 121 can, for example, depict in greater detail components that can be provided for the capacity management system 101 shown in FIG. 1A. Specifically, the capacity management system 121 can include a central component 121A and a node component 121B in accordance with the embodiment depicted in FIG. 1B. The central component 121A of the computing capacity management system 121 can be operable to effectively control the computing capacity of the database system as whole and/or coordinate or manage the capacity control activities as performed locally at one or more database nodes 1 to Node N. In contrast, a node component 121B can primarily control and/or monitor the computing capacity of a particular database node (i.e., a node I) without controlling or having knowledge about the manner in which the capacity of any other database nodes, or the capacity of the multi-node database system 120 as a whole, is being controlled.

Generally, the computing capacity management system 121 of the multi-node database system 120 can be operable to obtain (e.g., receive, determine) an overall target capacity for the multi-node database system 120 and effectively set and/or change the computing capacity of the multi-node database system 120 to the overall target capacity. As described in greater detail below, it will be appreciated that the computing capacity management system 121 can also be operable to maintain the overall capacity for the multi-node database system 120 at an overall target or desired computing capacity. By way of example, the central component 121A may obtain an overall target capacity for the multi-node database system 120, and based on the overall target capacity, determine an individual target capacity for a particular database node. Accordingly, the central component 121A can, for example, be operable to communicate the determined individual target capacity of a particular database node (Node I) to its respective node component 121-BI. The node component 121-BI can, in turn, set and/or maintain the computing capacity of the database node I to the determined individual target capacity as communicated by the central component 121A. Other database nodes can operate in a similar manner to set and maintain their node capacity at a target capacity. As a result the overall target computing capacity for the database system can be achieved.

For example, a target overall computing capacity which is half (or 50 percent) of the full computing capacity can be received as input by the computing capacity management system 121 as a target computing capacity for the database 120. In the example, the central component 121A may determine to change the computing capacity of each one of the database nodes (Node 1-Node N) from their current capacity, which may be at full computing capacity to half computing capacity. As such, central component 121A may be operable to communicate with all of the node components (121B1-121-BN) to effectively cause them to change their capacities from full to half computing capacity.

Alternatively, central component 121A may determine to set the capacities of the individual database nodes (Node 1-Node N) to various levels individually to achieve the desired overall target capacity. As such, central component 121A may cause the capacity of a first database node to be changed form full to half capacity, while the computing capacity of a second database node may be increased from twenty five (25) percent to fifty (50) percent, the computing capacity of a third database node may be set to seventy (70) percent computing capacity, the computing capacity of a third database node may be set to thirty (30) percent computing, and so on, in order to achieve a desired overall capacity, namely, half or fifty (50) percent overall capacity for the multi-node database system 120. As another example, if one or more database nodes of the multi-node database system 120 fail, the capacity of the database nodes that are still operable can be adjusted to compensate for the loss of one or more nodes in order to still achieve an overall capacity for a database. In the example, the capacity of the database nodes can be readjusted when all database nodes become operable again.

To further elaborate, FIG. 1C depicts a method 150 for controlling capacity of a database system in accordance with one embodiment of the invention. Method 150 can, for example, be performed by the capacity management system 101 (shown in FIG. 1A) or the computing capacity management system 121 (shown in FIG. 1B). Referring now to FIG. 1C, optionally, it can be determined (152) whether to change the capacity of a database system from its current capacity. As those skilled in the art will readily appreciate, the determination (152) can, for example, represent a design or programming choice and/or can be made based on input and/or one or more criteria (e.g., determining a need to change the capacity to handle a high priority request or performing system upgrade, receiving a target capacity as input, receiving a command to change the capacity). In effect, method 150 can wait for a determination (152) to change the capacity of the database system unless it is determined (154) to end the method 150. As such, the method 150 can, for example, end as a result of receiving input, system shutdown, etc. However, if it is determined (152) to change the capacity of the database system, the capacity of the database system can be changed (156) from it current capacity to a different capacity. The capacity of the database system can, for example, be changed by causing the usage capacity of at least one of the resources to be changed from a current usage capacity to a different usage capacity. Thereafter, method 150 can proceed to determine whether to change the capacity of the database system in a similar manner as noted above. Method 500 can end if it is determined (154) to end it.

As noted above, a capacity management system (e.g., capacity management system 101 depicted in FIG. 1A, computing capacity management system 121 depicted in FIG. 1B) can be operable to change or vary the capacity of the database system at execution time or runtime, in a dynamic manner in accordance with aspect of the invention.

To further elaborate, FIG. 2 depicts a method 200 for processing data by a database (or database system) in accordance with one embodiment of the invention. Method 200 can, for example, be performed by the capacity management system 101 (shown in FIG. 1A) or the computing capacity management system 121 (shown in FIG. 1B).

Referring to FIG. 2, initially, the computing capacity of a database is set (202) to a first capacity (e.g., a first computing capacity). As noted above, the capacity of a database can, for example, be set to a particular value by setting (e.g., changing, adjusting, limiting) the usage capacity of one or more resources (e.g., processors, access to I/O operations) associated with the database. Next, the database can process data and various database operations can be performed. In other words, conventional database operations can be performed. Specifically, it can be determined (204) whether a database request or query has been received. Accordingly, processing of a database request can be initiated (206). In effect, method 200 can continue to process data and perform database operations unless it is determined (208) to end processing of the data and the performing database operations. The database operations can, for example, end as a result of a system shutdown or receiving authorized input. As such, the method 200 can end if it is determined (208) to end the processing of data and performing database operations.

However, it should be noted that while the data is being processed and/or database operations are being performed by the database, it can be determined (210) whether to change the capacity of the database. The determination (210) can, for example, be made based on input indicative of change, or based on one or more criteria (e.g., one or more system conditions, periodic adjustments, need to meet service goals). If it is determined (210) to change the capacity of the database, it can also be determined (212) whether to determine a capacity (i.e. different or new capacity) for the database. It should be noted that a different capacity can be received as input so there may not be a need to determine (214) a capacity for the database. However, if it is determined (212) to determine a capacity for the database, a capacity which is different than the first capacity can be determined (214) for the database. It will be appreciated by those skilled in the art, a capacity for the database can be determined based on one or more criteria (e.g., the extent in which excess capacity is needed to perform maintenance, periodic adjustment, past usage and/or anticipated usage, amount of money paid for capacity). In any case, if it determined (210) to change the capacity of the database from the first capacity to a different capacity, regardless of whether a capacity is determined (212) or not, the capacity of the database is set (214) to a second capacity, different than the first capacity (i.e., higher or lower than the first capacity). The capacity of the database can be set to the second capacity, for example, by affecting the usage capacity of one or more resources associated with the database (i.e., by effectively increasing or decreasing the usage capacity or extent of allowed usage of one or more resources associated with the database). After, the capacity of the database has been effectively changed by setting (214) the capacity to a second capacity, the method 200 can proceed determine (210) whether to change the capacity of the database. As result, the capacity of the database can be changed (216) in a dynamic manner at runtime or execution time, while the data is being processed and database operations are being performed by the database (i.e., the database is operational and/or active) in a similar manner as discussed above. Method 200 ends if it determined (208) to the end the processing of data and database operations.

As noted above, it can be determined whether to change the current capacity of a database (or database system) based on input indicative of change, or one or more criteria (e.g., one or more system conditions, periodic adjustments, need to meet service goals). By way of example, it can be determined to extend or increase the current capacity of a database in order to meet a system requirement (e.g., a Service Level Agreement (SLA) requiring high priority database queries to be processed within a determined time period, system maintenance or update). As such, it can, for example, be determined to allow excess capacity beyond a target capacity (e.g., fifty (50) percent) in order to meet an SLA or to allow a system update. It should also be noted that excess system capacity can also be measured and accounted (e.g., billed) in accordance with one aspect of the invention.

To further elaborate, FIG. 3 depicts a method 300 for controlling the capacity of a database (or a database system) in accordance with another embodiment of the invention. Method 300 can, for example, be performed by the capacity management system 101 (shown in FIG. 1A) or the computing capacity management system 121 (shown in FIG. 1B).

Referring to FIG. 3, initially, a target capacity for the database can be obtained (302). The target capacity can, for example, be received as input or determined based on one or more criteria (e.g., capacity selected and/or paid for by a user and/or customer of a database, types and/or number of database requests currently pending). It should be noted that the target database capacity can, for example, be representative of an overall target capacity for a database or a database system (e.g., a multi-node database system), or a specific target capacity for one or more database nodes of a multimode database). After the target capacity of the database is obtained (302), the capacity of the database or a portion of the database (e.g., one or more database nodes of a multimode database) can be set (304) to the target system capacity.

As will be described in greater detail below, the capacity of at least a part of the database can be set (304) based on a target capacity by using one or a combination of various techniques. By way of example, one or more database tasks or activities can be regulated with respect to the access to one or more resources of the database based on the target capacity. In other words, the extent to which one or more database tasks or activities can access one or more resources of the database (e.g., access to processor for execution time, access to I/O operations) can be controlled based on a target capacity in order to effectively set the capacity of at least a portion of the database to the target capacity. As another example, the effective processing rate and/or clock rate of one or more processors of the database can be set based on the target capacity.

In any case, in addition to setting the capacity of at least a portion of the database based on the target capacity, monitoring can be initiated (306) if it has not been initiated already. This monitoring can, for example, include monitoring the usage of one or more resources and/or one or more system conditions (e.g., monitoring execution of one or more database tasks and resources consumed by them, monitoring for conditions that are programmed to trigger change in the capacity of the database).

After the monitoring has been initiated (306) it is determined (308) whether to change the capacity of at least a portion of the database from its current capacity (e.g., whether to change the capacity of a database from a target capacity under which the database is configured to operate under normal circumstances). It should be noted that the determination (308) can be made based on the monitoring data obtained as a result of the monitoring that has been initiated (306) and after at least a portion of the database has been set (304) or configured to operate at a target capacity. By way of example, monitoring (306) of one or more system conditions can indicate a need to increase the capacity. As such, it can be determined (308) to allow the database to exceed its target capacity at least for a period of time.

Generally, if it is determined (308) to change the capacity of at least a portion of the database, the capacity of at least one portion of the database can be increased or decreased (310). By way of example, the overall capacity of a multi-node database system can be increased from its target capacity, fifty (50) percent, to seventy five (75) percent in order to meet a need or a requirement.

It should be noted that capacity and/or actual usage can optionally be monitored and stored (e.g., measured and recorded) based on the monitoring (306) of the tasks and the resources consumed by them. As such, it can optionally be determined (312) whether to monitor (e.g., measure) the capacity and/or actual usage of the capacity provided. Consequently, the capacity and/or actual usage of the capacity of a database can be monitored and stored (314). By way of example, capacity used beyond a target capacity (or excess capacity) can be measured based on monitoring the usage of one or more resources consumed by database tasks or activities. Usage of resources in an excess of the target capacity can, for example, be billed at a cost or as an additional cost beyond the target capacity.

After the capacity of at least a portion of database has changed (312) it can be determined (316) whether to set the capacity of at least a portion of the database back to the target capacity. Accordingly, the capacity of at least a portion of the database can be set (304) to the target capacity again and the method 300 can proceed in a similar manner as discussed above. However, if it is determined (316) not to set the capacity of at least a portion of the database to the target capacity, the method 300 can proceed to determine whether to change the capacity of at least a portion of the database. In effect, method 300 can wait for a determination (308) to change the capacity of at least a portion of the database unless it is determined (318) to end the method 300, for example, based on input provided by a database administrator, or when the system is to be shut down.

More Specific Techniques for Controlling Resources of a Database

As noted above, the capacity of database can be controlled by effectively controlling the usage capacity of one or more resources associated with a database in accordance with one aspect of the invention. In particular, access to the computing resources of a database can be controlled in order to effectively control the computing capacity of a database.

Typically, a task (e.g., a database query) requires access to various computing resources (e.g., access to a processor or execution time, access to I/O operations including reading data stored in a database and writing data to the database). In other words, access to resources required by a database can be effectively regulated in accordance with one aspect of the invention. It will be appreciated that a capacity management system can effectively regulate access to resources of a database in accordance with one embodiment of the invention.

To further elaborate, FIG. 4A depicts a capacity management system 400 for a database in accordance with one embodiment of the invention. The capacity management system 400 can represent in a greater detail the components that can be provided for the capacity management system 101 (shown in FIG. 1A) or the computing capacity management system 201 (shown in FIG. 1B). It should be noted that one or more components of the capacity management system 400 can, for example, be provided as central component for a multi-node database and/or can be provided as a node component for a particular database node of a multi-node database.

Referring to FIG. 4A, the capacity management system 400 can include a regulator (or a usage regulator) 402 operable to effectively regulate access to various resources R1-RN. More specifically, regulator 402 can regulate access to resources R1-RN when the database is actively processing data and requests (e.g., when queries made by one or more users of a database are being processed by the database). Data and requests can be processed by a Database Management System (DBMS) (e.g., a Relational Database Management System (RDBMS) 404. Conceptually, DBMS 404 can be provided over an Operating System (O.S.) 407. DBMS 404 can effectively request access to resources provided and/or under the control of the OS 407 which may include one or all of the resources R1-RN. Typically, resources R1-RN can include storage for storing data used by the DBMS 404, as well as one or more processors (e.g., Central Processing Units (CPUs).

As suggested by FIG. 4A, one or more of the resources R1-RN can be part of the O.S. 407. By in large, DBMS 404 and O.S. 407 can be considered to collectively make at least a significant part of a database or database system that could also include storage for storing data (not shown). Conceptually, the DBMS 404 may generate various database tasks DBT1-DBTN as data or requests are processed or database operations are being effectively managed by the DBMS 404. For example, in response to various database queries made by one or more users of the database, a number of database tasks DBT1-DBTN can be generated.

Typically, completion of a database task DBTI requires execution time and access to one or more I/O operations in order to complete. Generally, the regulator 402 can regulate the database tasks DBT1-DBTN at least with respect to access to the resources R1-RN.

Regulator 412 can, for example, include or cooperate with, a scheduler that effectively regulates or controls the amount of time a particular task DBTI is to wait before it can access a particular resource RJ and/or the amount of access time a particular task DBTI has with respect to a resource RJ when access is granted. The scheduler can effectively schedule the access time of the database tasks DBT1-DBTN with respect to the resources R1-RN based on a target capacity. As such, when the database is regulated to be at full capacity, the regulator 402 may schedule a particular task DBTI to execute as soon as possible and for as long as possible, of course, in consideration of other database tasks, especially those that may have a higher priority.

However, if the capacity of the database is regulated by the regulator 402 to be at half of its full capacity, the regulator 402 may, for example, cause an additional delay (i.e., relative to delay that can be experienced at full capacity) before a particular task DBTI is executed and/or is given access, for example, to an I/O resource, such as a read or write to the database. Similarly, at half of full capacity, the regulator 402 may allow a particular task DBTI to execute for a shorter time than it would have if the database was regulated (or allowed to operate) at full capacity and/or may allow a shorter access time to I/O operations required by a particular database task DBTI. As a result, a task DBTI may, for example, take a significantly longer time (e.g., about two (2) times longer) to complete when the database is at half capacity than it would if the database was operating at full capacity.

Referring to FIG. 4A again, it should also be noted that the regulator 402 can receive input from a capacity (or capacity tuning) manager 405 which can effectively manage the capacity of the database by providing input indicative of a target or desired capacity under which the regulator 402 is to regulate access to the resources R1-RN. The capacity manager 405 can determine a target or desired capacity for the regulator 402 at least partially based on the monitoring data or information provided by a monitor 406. The monitor 406 can monitor usage of the resources R1-RN, as well as the progress of the database tasks DBT1-DBTN in order to provide the monitoring data to the capacity manager 405.

More specifically, the monitor 406 can monitor usage of the resources R1-RN by the database tasks DBT1-DBTN, at least some of which may also be effectively regulated by the regulator 402.

It should be noted that the monitor 406 can also be operable to determine the overall usage of the resources R1-RN, for example, by obtaining the information from the O.S. 407. This means that the monitor 406 can be operable to monitor usage of the resources R1-RN by activities that may not be directly related to the DBMS 404 or activities that may not be directly controlled or regulated by the regulator 402 (e.g., system tasks, OS tasks, OS dump, Gateway, applications outside the database system, Network applications, such as TCP/IP, CLI, MTDP, MOSI). Thus, the monitor 406 can determine the usage of the resources R1-RN by the database tasks DBT1-DBTN, as well as the overall usage of the resources R1-RN, which also includes usage by tasks or activities other than the database tasks DBT1-DBTN (e.g., non-database tasks). As such, the monitor 406 can provide the regulator 402 and/or the capacity manager 405 with resource usage information indicative of the extent of usage of the resources R1-RN by each or all of the database tasks DBT1-DBTN, as well as the extent of total usage of the resources R1-RN by all tasks and activities, including those that may not be directly related to the DBMS 404 and/or controllable by the regulator 402.

In addition, monitor 406 can monitor the progress of a database task DBTI and/or estimate time required to complete a database DBTI task. The monitoring data provided by the monitor 406 can affect the regulation activities of the regulator 402, either directly or indirectly, via the capacity manager 405.

Referring to FIG. 4A yet again, it should also be noted that an interface 410 (e.g., a User Interface (UI), a Graphical User Interface (GUI)) may be optionally provided by or for the capacity management system 400. The interface 410 can be operable to receive input (e.g., a target capacity) and provide output (e.g., current over all system capacity, system capacity of an individual database node, general or overall resource usage information, overall resource usage information pertaining to database tasks or activities, one or more specific resource usage information pertaining to one or more database tasks).

To further elaborate, FIG. 4B depicts a method 420 for controlling the capacity of a database in accordance with yet another embodiment of the invention. Method 420 can, for example, be performed by the capacity management system 400 depicted in FIG. 4A. Referring to FIG. 4B, initially, a target capacity for a database is obtained (422). The target capacity can, for example, be received as input or determined based on one or more criteria (e.g., capacity selected and/or paid for by a user and/or customer of the database, types and/or quantity of data requests currently pending). It should be noted that the target database capacity can, for example, be representative of an overall target capacity for a database or a database system (e.g., a multi-node database), or a target capacity for one or more particular database nodes of a multimode database).

Next, based on the target capacity, one or more database tasks or activities (e.g., one or more database queries, I/O operations) are regulated with respect to their access to one or more resources associated with the database (e.g., access to a processor or execution time, access to a read or write operation). By way of example, a target capacity of half of full capacity can result in causing a determined delay in execution of some or all of the queries currently pending, as well as any additional queries received later after the capacity is set or regulated to be half of its full capacity. This delay can, for example, be made in direct proportion to the target capacity and can be significantly longer than the delay that would be experienced when the database is regulated at the full capacity. It will be appreciated that the delay can, for example, be caused by scheduling the database activities based on the target capacity, as will be described in greater detail below. Referring back to FIG. 4B, method 420 ends after one or more database tasks or activities are regulated (424) with respect to their access to one or more resources associated with the database based on the target capacity.

As noted above, a scheduling technique can be used to cause delays in processing of the data and/or performing tasks by a database. The delays can be made in proportion to a target or desired capacity for the database in accordance with one aspect of the invention.

To elaborate further, FIG. 4C depicts a method 430 for processing one or more database tasks or activities in accordance with one embodiment of the invention. Method 430 can, for example, represent in greater detail operations that may be performed to regulate (424) one or more database tasks based on target capacity in accordance to the method 420 depicted in FIG. 4B.

Referring now to FIG. 4C, initially, it is determined (432) whether there is at least one database task or activity to process. In effect, method 430 can wait for a determination (432) that one or more database tasks or activities are to be processed. By way of example, it can be determined (432) that one or more database queries have been submitted for processing by the database.

If it is determined (432) that there is at least one database task or activity to process, the current target capacity of the database is obtained (434). In addition, one or more database tasks or activities are scheduled for execution and/or for access to other computing resources (e.g., access to an I/O operation) based on the current target capacity of the database. Typically, the scheduling (436) causes relatively longer delays for target capacities that are relatively lower with respect to full capacity. As such, a target capacity of, for example, fifty (50) percent can cause relatively longer delays in completion of one or more database tasks or activities than the delays that would be caused by a target capacity of seventy five (75) percent, but a target capacity of twenty five (25) percent could cause a significantly longer delay than the delay when the target capacity is at fifty (50) percent, and so on.

After the one or more database tasks or activities are scheduled (436), it is determined (438) whether at least one database task or activity is still pending. In other words, it can be determined (438) whether at least one database task or activity has not completed. If it is determined (438) that no tasks or activities are still pending, the method 430 can effectively wait (432) for one or more tasks or activities to be received for processing.

However, if it is determined (438) that least one database task or activity is still pending, it can be determined (440) whether to adjust the scheduling of one or more tasks or activities that are still pending. By way of example, if the target capacity of the database has changed, it can be determined to reschedule one or more tasks or activities. As a result, execution of one or more tasks can be rescheduled and/or access to other computing resources can be rescheduled based on the current target capacity which is different than the target capacity at the time access to resources was initially scheduled for the one or more tasks or activities.

As such, if it determined (440) to adjust the scheduling of one or more pending tasks or activities, the current target capacity can be obtained (434) and one or more tasks or activities that are pending can be rescheduled based on the current target capacity in a similar manner as discussed above.

Closed-loop Capacity Management Architecture

In accordance with yet another aspect of the invention, a “closed-loop” capacity management architecture can be provided. As such, it will be appreciated that a capacity management system 400 (depicted in FIG. 4A) can, for example, be provided using or in a “closed-loop” capacity management architecture in accordance with one embodiment of the invention. The “closed-loop” capacity management architecture can, for example, be similar to the closed-loop workload management architecture described in U.S. Pat. No. 7,657,501, entitled: “Regulating the Work Load of a Database System,” by “Brown et al.” and filed on Aug. 10, 2004, which is hereby incorporated by reference herein in its entirety and for all purposes. As described in greater detail in the U.S. Pat. No. 7,657,501, entitled: “Regulating the Work Load of a Database System,” a system provided in “closed-loop” workload management architecture can satisfying a set of workload-specific goals.

With respect to managing capacity, a system that can satisfy capacity goals or requirements in a “closed-loop” capacity management architecture will be described below in accordance with one embodiment of the invention. It should be noted that workload management and capacity management can be provided together in a system to allow meeting workload and capacity goals and requirements in accordance with another aspect of the invention. Since it may be more instructive to discuss a “closed-loop” system that can manage both workload and capacity of a database, a “closed-loop” capacity and workload management system is discussed below for the sake of comprehensiveness. However, as will be readily understood by those skilled in the art, it is not necessary to manage both capacity and workload of the database as each of these features can be provided separately even though it may be desirable to provide both of these features for some applications.

As described in the U.S. Pat. No. 7,657,501, entitled: “REGULATING THE WORK LOAD OF A DATABASE SYSTEM,” an automated goal-oriented workload management system can support complex workloads and can self-adjust to various types of workloads. Major operational phases can include: 1) assigning a set of incoming request characteristics to workload groups, assigning the workload groups to priority classes, and assigning goals (called Service Level Goals or SLGs) to the workload groups; 2) monitoring the execution of the workload groups against their goals; 3) regulating (adjusting and managing) the workload flow and priorities to achieve the SLGs; 4) recommending adjustments to workload definitions (e.g. by splitting or merging workload definitions) in order to better isolate the subset of the workload that requires different workload management than the remainder of the original workload; and 5) correlating the results of the workload and taking action to improve performance.

The performance improvement can be accomplished in several ways: 1) through performance tuning recommendations such as the creation or change in index definitions or other supplements to table data, or to recollect statistics, or other performance tuning actions, 2) through capacity planning recommendations, for example increasing system power, 3) through utilization of results to enable optimizer adaptive feedback, and 4) through recommending adjustments to SLGs of one workload to better complement the SLGs of another workload that it might be impacting. Recommendations can either be enacted automatically, or after “consultation” with the database administrator (“DBA”).

FIG. 5 depicts a “closed-loop” capacity and workload management system 500 in accordance with one embodiment of the invention. Referring to FIG. 5, an administrator 403 can provide a GUI for defining rules 409 that can, for example, include capacity management rules, as well as workloads and their SLGs, and other workload or capacity management requirements. The administrator 403 accesses data in logs 407, including a query log and receives input including capacity and performance related inputs. The administrator 403 can be a primary interface for the DBA. The administrator 403 can also establish rules 409, including capacity and workload rules, which can be accessed and used by other components of the closed-loop capacity management and workload management system 500.

A monitor 411 can effectively provide a top level dashboard view and the ability to drill down to various details of overall and individualized component capacity at various times, as well as workload group performance such as aggregate execution time, execution time by request, aggregate resource consumption, resource consumption by request, etc. Such data is stored in the query log and other logs 407 available to the monitor 411. The monitor 411 also includes processes that initiate the performance improvement mechanisms listed above and processes that provide long term trend reporting, which may include providing performance improvement recommendations. Some of the monitor 411 functionality may be performed by a regulator 415 which can monitor 411 capacity and workloads, for example, by using internal messaging system.

The regulator 415 can dynamically adjust system settings including capacity and/or projects performance issues and can either alert the database administrator (DBA) or user to take action, for example, by communication through the monitor 411, which is capable of providing alerts, or through the exception log, providing a way for applications and their users to become aware of, and take action on, actions taken by the regulator 415. Alternatively, the regulator 415 can automatically take action by deferring requests or executing requests with the appropriate priority to yield the best solution given requirements defined by the administrator 405.

FIG. 6 depicts in greater detail the regulator 415 in accordance with one embodiment of the invention. The regulator 415 can effectively regulate processing of requests based on current capacity and/or workload of a database by dynamically monitoring the capacity and workload characteristics using rules or other heuristics based on past and current performance of the system that guide two feedback mechanisms. It can do this before the request begins execution and at periodic intervals during query execution. Prior to query execution, the current capacity can be considered. Further, the workload characteristics of the query can be examined (e.g., an incoming request can be examined to determine in which workload group it belongs based on criteria).

As shown in FIG. 6, the regulator 415 can receive one or more requests, each of which can be assigned by an assignment process (block 605) to a workload group and, optionally, a priority class, in accordance with the workload rules 409 a. The assigned requests can then be passed to a query (delay) manager 610. In addition, capacity rules and/or input 409 b can be passed to the query (delay) manager 610. In general, the query (delay) manager 610 monitors the workload performance compared to the system capacity and/or the workload rules and either allows the request to be executed immediately or holds it for later execution, as described below. If the request is to be executed immediately, the query (delay) manager 610 places the request in the priority class bucket 620 a-s corresponding to the priority class to which the request was assigned by the administrator 405. A request processor under control of a priority scheduler facility (PSF) 625 selects queries from the priority class buckets 620 a-s, in an order determined by the priority associated with each of the buckets, and executes it, as represented by the processing block 630 on FIG. 6.

It should be noted that the query (delay) manager 610 and/or request processor under control of a priority scheduler facility (PSF) 625 can individually or collectively be operable to effectively delay processing of a request based on a current, a desired, or a target capacity. The request processor 625 can also monitor the request processing and report throughput information, for example, for each request and for each workgroup, to an exception monitoring process 615. The exception monitoring process 615 can compare the throughput with the workload rules 409 and can store any exceptions (e.g., throughput deviations from the workload rules) in the exception log/queue. In addition, the exception monitoring process 615 can provide system resource allocation adjustments to the request processor 625, which can adjust system resource allocation accordingly, e.g., by adjusting the priority scheduler weights. Further, the exception monitoring process 615 provides data regarding the workgroup performance against workload rules to the query (delay) manager 610, which can use the data to determine whether to delay incoming requests, depending on the workload group to which the request is assigned.

As shown in FIG. 6, the system provides two feedback loops, indicated by the circular arrows shown in the drawing. The first feedback loop includes the request processor 625 and the exception monitoring process 615. In this first feedback loop, the system monitors on a short-term basis the execution of requests to detect deviations greater than a short-term threshold from the defined service level for the workload group to which the requests were defined. If such deviations are detected, the DBMS is adjusted, e.g., by adjusting the assignment of system resources to workload groups. The second feedback loop includes the query (delay) manager 610, the request processor 625 and the exception monitoring process 615. In this second feedback loop, the system monitors on a long-term basis to detect deviations from the expected level of service greater than a long-term threshold. If it does, the system adjusts the execution of requests, e.g., by delaying, swapping out or aborting requests, to better provide the expected level of service. Note that swapping out requests is one form of memory control in the sense that before a request is swapped out it consumes memory and after it is swapped out it does not consume memory. While this is the preferable form of memory control, other forms, in which the amount of memory dedicated to an executing request can be adjusted as part of the feedback loop, are also possible.

FIG. 7 depicts in greater detail query (delay) manager 610 (also shown in FIG. 6) in accordance with one embodiment of the invention. The query (delay) manager 610 receives an assigned request as an input. A comparator 705 determines if the request should be queued or released for execution. It does this based on the current or input capacity and/or by determining the workload group assignment for the request and comparing that workload group's performance against the workload rules, provided by the exception monitoring process 615. For example, the comparator 705 may examine the concurrency level of requests being executed under the workload group to which the request is assigned. Further, the comparator may compare the workload group's performance against other workload rules. If the comparator 705 determines that the request should not be executed, it places the request in a queue 710 along with any other requests for which execution has been delayed. The comparator 705 continues to monitor the workgroup's performance against the capacity and/or workload rules and when it reaches an acceptable level, it extracts the request from the queue 710 and releases the request for execution. In some cases, it may not be necessary for the request to be stored in the queue to wait for workgroup performance to reach a particular level, in which case it is released immediately for execution. Once a request is released for execution it is dispatched (block 715) to priority class buckets 620 a-s, where it will await retrieval by the request processor 625.

FIG. 8 depicts in greater detail an exception monitoring 615 in accordance with one embodiment of the invention. Exception monitoring 615 receives throughput information from the request processor 625. A workload performance to capacity and/or workload rules comparator 805 compares the received throughput information to the capacity rules and/or workload rules and logs any deviations that it finds in the exception log/queue 510. The capacity rules can effectively define performance for a workload at various capacities. The comparator 805 can also generate the workload performance against capacity and workload rules information which can be provided to the query (delay) manager 610. To determine what adjustments to the system resources are necessary, the exception monitoring process calculates a ‘performance goal index’ (PGI) for each workload group (block 810), where PGI is defined as the observed average response time (derived from the throughput information) divided by the response time goal (derived from the capacity and/or workload rules). Because it is normalized relative to the goal, the PGI is a useful indicator of performance that allows comparisons across workload groups. The exception monitoring process can adjust the allocation of system resources among the workload groups (block 815) using various techniques. For example, one technique is to minimize the maximum PGI for all workload groups for which defined goals exist. As another example, is to minimize the maximum PGI for the highest priority workload groups first, potentially at the expense of the lower priority workload groups, before minimizing the maximum PGI for the lower priority workload groups. These techniques can be specified by a DBA in advance through the administrator. An indication in the form of a system resource allocation adjustment is transmitted to the request processor 625. By seeking to minimize the maximum PGI for all workload groups, the system treats the overall workload of the system rather than simply attempting to improve performance for a single workload. In most cases, the system will reject a solution that reduces the PGI for one workload group while rendering the PGI for another workload group unacceptable. This approach means that the system does not have to maintain specific response times very accurately. Rather, it only needs to determine the correct relative or average response times when comparing between different workload groups.

FIG. 9A depicts in greater detail an exception monitor 615 as a part of a regulator 415 in accordance with one embodiment of the invention. Exception monitor 615 includes a subsystem condition detector and adjuster (SSCDA) 5105 and a system condition detector and adjuster (SCDA) 5110. As shown in FIG. 9A, in one example system there is one SCDA 5110 for the entire system. In some example systems, one or more backup SCDAs (not shown) are also provided that will operate in the event that SCDA 5110 malfunctions.

As shown in FIG. 9B, there can be one SSCDA 5105 per dispatcher. However, more than one SSCDA 5105 per dispatcher can be provided. In addition, some systems may have only one dispatcher per parsing engine, although this is not a limitation of the concept described herein. Further, in some systems each parsing engine may run on a single node or across multiple nodes. In some example systems, each node will include a single parsing engine. Thus, for example, there may be one SSCDA per AMP, one per parsing engine, or one per node.

Returning to FIG. 9A, the SCDA monitors and controls resource consumption at the system level, while the SSCDA monitors and controls resource consumption at the subsystem level, where in some example systems, a subsystem corresponds with a single dispatcher. Some subsystems may correspond to a share of a dispatcher. Further, a subsystem may correspond to more than one dispatcher. Each SSCDA monitors and controls, in a closed loop fashion, resource consumption associated with a single subsystem. An SSCDA monitors throughput information that it receives from the request processor 625 and compares that performance information to the workload rules 409. The SSCDA then adjusts the resource allocation in the request processor 625 to better meet the workload rules.

The SCDA receives system conditions, compares the conditions to the workload rules, and adjusts the system resource allocations to better meet the system conditions. For convenience, FIG. 9A shows the SCDA receiving inputs from and sending outputs to the request processor 625. In another exemplary system, the inputs and outputs to and from the SCDA are handled as described below with respect to FIG. 9C.

Generally, the SSCDA provides real-time closed-loop control over subsystem resource allocation with the loop having a fairly broad bandwidth. The SCDA provides real-time closed-loop control over system resource allocation with the loop having a narrower bandwidth. The SCDA provides real-time closed-loop control over system resource allocation with the loop having a narrower bandwidth. Further, while the SSCDA controls subsystem resources and the SCDA controls system resources, in many cases subsystem resources and system resources are the same. The SCDA has a higher level view of the state of resource allocation because it is aware, at some level as discussed with respect to FIG. 9C, of the state of resource allocation of all subsystems, while each SSCDA is generally only aware of the state of its own resource allocation. A system may include some resources that are shared at a system level. Such resources would be truly system resources controlled by the SCDA.

One example of the way that the SCDA 5110 may monitor and control system resource allocations is illustrated in FIG. 9C. The SSCDAs are arranged in a tree structure, with one SSCDA (the root SSCDA 5305) at the top of the tree, one or more SSCDAs (leaf SSCDAs, e.g. leaf SSCDA 5310) at the bottom of the tree, and one or more intermediate SSCDAs (e.g. intermediate SSCDA 5315) between the root SSCDA and the leaf SSCDAs. Each SSCDA, except the root SSCDA 5305, has a parent SSCDA (i.e. the immediately-higher SSCDA in the tree) and each SSCDA, except the leaf SSCDA, has one or more child SSCDA (i.e. the immediately lower SSCDA in the tree). For example, in FIG. 9C, SSCDA 5315 is the parent of SSCDA 5310 and the child of SSCDA 5320.

In the example shown in FIG. 9C, the tree is a binary tree. It will be understood that other types of trees will fall within the scope of the appended claims. Further, while the tree in FIG. 9C is symmetrical, symmetry is not a limitation. The SCDA 5110 gathers system resource information by broadcasting to all SSCDAs a request that they report their current resource consumption. In one example system, each SSCDA gathers the information related to its resource consumption, as well as that of its children SSCDAs, and reports the compiled resource consumption information to its parent SSCDA. In one example system, each SSCDA waits until it has received resource consumption information from its children before forwarding the compiled resource consumption information to its parent. In that way, the resource consumption information is compiled from the bottom of the tree to the top. When the root SSCDA 5305 compiles its resource consumption information with that which is reported to it by its children SSCDAs, it will have complete resource consumption information for the SSCDAs in the system. The root SSCDA 5305 will report that complete information to the SCDA. The SCDA will add to that information any resource consumption information that is available only at the system level and make its resource allocation adjustments based on those two sets of information.

In another exemplary system, each of the SSCDAs communicates its resource consumption information directly to the SCDA 5110. The SCDA 5110 compiles the information it receives from the SSCDAs, adds system level resource consumption information, to the extent there is any, and makes its resource allocation adjustments based on the resulting set of information.

There are at least two ways by which the SCDA 5110 can implement its adjustments to the allocation of system resources. The first, illustrated in FIG. 9A, is for the SCDA 5110 to communicate such adjustments to the request processor 625. The request processor 625 implements the adjustments to accomplish the resource allocation adjustments.

Alternatively, the SCDA 5110 can communicate its adjustments to the SSCDAs in the system, either directly or by passing them down the tree illustrated in FIG. 53. In either case, the SSCDAs incorporate the SCDA's resource allocation adjustments in the subsystem resource allocation adjustments that it sends to the request processor 625.

Capacity Management for Multi-node, Parallel Database Systems

The techniques described above are especially suitable for multi-node, parallel databases, including those that use a massively parallel processing (MPP) architecture or system. To further elaborate FIG. 10 depicts a database node 1105 of a database system or database management system (DBMS) 1000 in accordance with one embodiment of the invention. The database system 1000 can, for example, be provided as a Teradata Active Data Warehousing System.

FIG. 10 depicts an exemplary architecture for one database node 1105 ₁ of the DBMS 100 in accordance with one embodiment of the invention. The DBMS node 1105 ₁ includes one or more processing modules 1110-N connected by a network 1115, that manage the storage and retrieval of data in data-storage facilities 1120 _(1-N). Each of the processing modules 1110-N represent one or more physical processors or virtual processors, with one or more virtual processors running on one or more physical processors.

For the case in which one or more virtual processors are running on a single physical processor, the single physical processor swaps between the set of N virtual processors. For the case in which N virtual processors are running on an M-processor node, the node's operating system schedules the N virtual processors to run on its set of M physical processors. If there are four (4) virtual processors and four (4) physical processors, then typically each virtual processor would run on its own physical processor. If there are eight (8) virtual processors and four (4) physical processors, the operating system would schedule the eight (8) virtual processors against the four (4) physical processors, in which case swapping of the virtual processors would occur. Each of the processing modules 1110 _(1-N) manages a portion of a database stored in a corresponding one of the data-storage facilities 120 _(1-N). Each of the data-storage facilities 1120 _(1-N) can includes one or more storage devices (e.g., disk drives). The DBMS 1000 may include additional database nodes 1105 _(2-O) in addition to the node 1105 ₁. The additional database nodes 1105 _(2-O) are connected by extending the network 1115. Data can be stored in one or more tables in the data-storage facilities 1120 _(1-N). The rows 1125 _(1-Z) of the tables can be stored across multiple data-storage facilities 1120 _(1-N) to ensure that workload is distributed evenly across the processing modules 1110 _(1-N). A parsing engine 1130 organizes the storage of data and the distribution of table rows 1125 _(1-z) among the processing modules 1110 _(1-N). The parsing engine 1130 also coordinates the retrieval of data from the data-storage facilities 1120 _(1-N) in response to queries received, for example, from a user. The DBMS 1000 usually receives queries and commands to build tables in a standard format, such as SQL.

In one embodiment, the rows 1125 _(1-Z) are distributed across the data-storage facilities 1120 _(1-N) by the parsing engine 1130 in accordance with their primary index. The primary index defines the columns of the rows that are used for calculating a hash value. The function that produces the hash value from the values in the columns specified by the primary index is called the hash function. Some portion, possibly the entirety, of the hash value is designated a “hash bucket”. The hash buckets are assigned to data-storage facilities 1120 _(1-N) and associated processing modules 1110 _(1-N) by a hash bucket map. The characteristics of the columns chosen for the primary index determine how evenly the rows are distributed.

Referring to FIG. 10, it should be noted that a capacity management node component 1002 can be provided as a separate entity (or component, or module) or can be at least partially implemented in the parsing engine 1130. In addition, a capacity management central component 1004 can be provided as a central component that can effectively coordinate and/or manage the capacity of the DBMS 1000.

In one exemplary system, the parsing engine 1130 is made up of three components: a session control 1200, a parser 1205, and a dispatcher 1210, as shown in FIG. 11. The session control 1200 provides the logon and logoff function. It accepts a request for authorization to access the database, verifies it, and then either allows or disallows the access. When the session control 1200 allows a session to begin, a user may submit a SQL request, which is routed to the parser 1205. Regarding the dispatcher 1210, it should be noted that some monitoring functionality for capacity and workload management may be performed by a regulator (e.g., regulator 415). The Regulator can monitor capacity and workloads internally. It can, for example, do this by using internal messages sent from the AMPs to the dispatcher 1210. The dispatcher 1210 provides an internal status of every session and request running on the system. It does this by using internal messages sent from the AMPs to the dispatcher 1210. The dispatcher 1210 provides an internal status of every session and request running on the system. As such, at least part of a capacity management system (capacity management 1250) can be provided by the dispatcher 1210 which operates as a capacity and workload enhanced dispatcher in order to effectively manage capacity and/or workload in the DBMS 1000.

As illustrated in FIG. 12, the parser 1205 interprets the SQL request (block 1300), checks it for proper SQL syntax (block 1305), evaluates it semantically (block 1310), and consults a data dictionary to ensure that all of the objects specified in the SQL request actually exist and that the user has the authority to perform the request (block 1305). Finally, the parser 1205 runs an optimizer (block 1320), which generates the least expensive plan to perform the request.

System conditions that can be considered by DBMS can, for example, include: Memory—the amount of system and subsystem memory currently being used. It is possible that the system will include some memory that is shared among all of the subsystems. AMP worker tasks (AWT)—the number of available AWTs. An AWT is a thread or task within an AMP for performing the work assigned by a dispatcher. Each AMP has a predetermined number of AWTs in a pool available for processing. When a task is assigned to an AMP, one or more AWTs are assigned to complete the task. When the task is complete, the AWTs are released back into the pool. As an AMP is assigned tasks to perform, its available AWTs are reduced. As it completes tasks, its available AWTs are increased. FSG Cache—the amount of FSG cache that has been consumed. The FSG cache is physical memory that buffers data as it is being sent to or from the data storage facilities. Arrival Rates—the rate at which requests are arriving. Arrival rate can be broken down and used as a resource management tool at the workload basis. Co-existence—the co-existence of multiple types of hardware. Skew—the degree to which data (and therefore processing) is concentrated in one or more AMPs as compared to the other AMPs. Blocking (Locking)—the degree to which data access is blocked or locked because other processes are accessing data. Spool—the degree of consumption of disk space allocated to temporary storage. CPU—the number of instructions used per second. I/O—the datablock I/O transfer rate. Bynet latency—the amount of time necessary for a broadcast message to reach its destination.

The techniques for communication between the SCDA 5110 and the SSCDAs can, for example, be accomplished by a single process running across all of the nodes and all of the AMPS, by multiple processes, where each process executes on a separate AMP, or by processes that can run on more than one, but not all, of the AMPs. “Process” should be interpreted to mean any or all of these configurations.

Since the SCDA 5110 has access to the resource consumption information from all SSCDAs, it can make resource allocation adjustments that are mindful of meeting the system workload rules. It can, for example, adjust the resources allocated to a particular workload group on a system-wide basis, to make sure that the workload rules for that workload group are met. It can identify bottlenecks in performance and allocate resources to alleviate the bottleneck. It can remove resources from a workload group that is idling system resources. In general, the SCDA 5110 provides a system view of meeting workload rules while the SSCDAs provide a subsystem view.

Managing Services of a Database

As noted above, controlling the capacity of a database can be useful. In particular, the ability to dynamically control the capacity of a database can be a very useful, especially for relatively large databases. For example, Platform Metering COD (PM COD) can serve as a mechanism to dynamically exercise measured control over the resources associated with a database. As such, PM COD can be very useful, especially for large databases with many resources, including CPUs and I/O resources.

One useful feature of PM COD is that it can offer the ability to rapidly upgrade hardware resources in a convenient manner. For example, a system can be upgraded in increments, which may be more budget-friendly increments to a purchaser of the resources, by installing a larger level of resources than may be initially required at the time of purchase, and limiting or dialing down access to a subset of the installed resources not purchased yet. Additional capacity or access to installed resources can be provided as the need grows and may involve an agreement between the provider and purchaser.

It would also be very useful to provide a PM COD database that allows managing it services, in particular, its Service Level Requirements (SLRs) and Service Level Agreements (SLAs). However, assigning Service Level Requirements (SLRs) and meeting Service Level Agreements (SLAs) can be difficult, especially in database environments, where capacity may change from time to time, and at a given time, only a portion of the full capacity of the database may be made available (e.g., a PM COD environment, where only fifty (50) percent of the full capacity of CPUs and I/O resources have been made available).

For example, in applications the issue high volumes of requests that are highly variable in nature, assigning a fixed SLG could significantly slow down some requests while speeding up other requests beyond what may be desired. As such, requests issued to a virtually idle system can, for example, have response times ranging from a sub-second to several hours, where assigning a two (2) minute response time to all such requests could greatly impair the requests that are to be made in sub-seconds. This could over-burden the system as it attempts to complete hour-long requests in just 2 minutes. Some requests or work may not be that important, so resources can be provided to them as they become free after more important requests have been served.

Moreover, as will be appreciated by those skilled in the art, even if a SLG is set appropriately, meeting the SLG pursuant to a SLA can be challenging for a database or DBMS, especially in a PM COD environment where the capacity of the database may effectively change rapidly in a dynamic manner.

As noted above, in a system that allows controlling the capacity of a database in dynamic manner, excess capacity can be available and utilized for various applications, including managing service levels (e.g., SLGs, SLAs) for a database.

In accordance with one aspect of the invention, excess capacity of a capacity controlled environment can be used to manage services of levels of a database. For example, excess capacity can be used to meet one or more SLGs or SLAs). Generally, excess capacity can be capacity available beyond a configured or controlled level of capacity of a database environment at a given time. As such, in a database capacity configured or controlled to operate effectively at sixty (60) percent of its full capacity, an additional forty (40) percent is available. It should be noted that excess can be provided to the extent needed (e.g., 0.01 percent, 0.80 percent, one (1) percent, two (2) percent, eleven (11) percent, thirty (30) percent, forty (40) percent) to meet one or more SLAs in accordance with the invention.

In accordance with another aspect of the invention, excess capacity as provided and/or used, in particular to meet service levels of a database, can be measured in a capacity controlled database environment. As a result, new billing models can be provided for databases, including, for example, a “Pay on Demand” or “Pay as You Go” model can be provided, for example, per query and/or Work Load Definition (WD) basis.

To further elaborate, FIG. 13 depicts a computing environment 440 in accordance with one embodiment of the invention. Referring to FIG. 13, the computing environment 440 includes a database system 442 and multiple resources R1-RN, at least some of which can be part of the database system 442. As those skilled in the art will readily know, the database system 442 can be operable to store data in a database (not shown separately) effectively provided by the database system 442. The database system 442 can access at least one of the resources R1-RN to process data associated with the database.

Moreover, the database 442 can also be operable to regulate work (e.g., database tasks or activities). By way of example, the database 442 can regulate access or extent of access made by one or more database tasks to one or more of the resources R1-RN. As such, the database system 442 can, for example, include a capacity management system 101 operable to regulate one or more database tasks or activities with respect to access or extent of access to the resources R1-RN. Typically, in the database system 442, regulation of database work, such as, various database tasks or activities (e.g., database requests and queries) is relatively more useful. As such, database system 442 can be configured to regulate at least some work (e.g., non-database work, such as, system tasks or activities) but some activities (e.g., a non-database task or activity) may not be regulated in the database system 442. This work can, for example, be regulated by a database management 101 which can be provided in accordance with the techniques described above.

In effect, the capacity management system 101 can configure and/or control the capacity of the database system 442 so that a desired or a target capacity below the full capacity of the database system 442 can be achieved and/or maintained. As a result, excess capacity can be available but remain effectively unused and/or inaccessible by the database system 442.

It will be appreciated that in accordance with the embodiment depicted in FIG. 13, the excess capacity, which can remain effectively unused and/or inaccessible by the database system 442, can be made available by the capacity management system 101 to the database system 442 to manage one or more services or service requests (e.g., database requests or queries) 443 based on a service criteria. By way of example, one or more services or service requests 442 can be managed in accordance to one or more service levels (e.g., SLGs, SLAs). As such, the capacity management system 101 can be operable to obtain service data 447, including, for example, data pertaining to SLGs and SLAs associated with a service request 442. In the example, SLG or SLA data can be indicative of a desire or agreement to service a service request 442 within a determined amount of time (e.g., 1 minute after a database request or query has been submitted). To achieve the SLG or SLA, the capacity management system 101 can determine whether to use excess capacity to serve or process a service request 442.

It should be noted that a service request 442 can correspond to one or more tasks 445 that are effectively regulated and monitored by the capacity management system 101, for example, in accordance with one or more monitoring and regulation techniques discussed above. Based on the monitoring of the one or more tasks 445, the capacity management system 101 can determine that a SLG or SLA may not be achievable unless excess capacity is used to process one or more tasks 445 corresponding to one or more service requests 443. As a result, the capacity management system 101 can effectively allow excess capacity to be used to process the one or more tasks 445 so that a SLG or SLA can be met.

It will also be appreciated that the capacity management system 101 can be operable to selectively allow the excess capacity to be used only for processing of one or more tasks 445 which correspond to one or more service requests 443. However, generally, capacity management system 101 can allow excess capacity to be used to manage one or more services even though excess capacity may or may not be made available to other tasks or services.

Furthermore, the capacity management system 101 can also be configured to measure excess capacity provided and/or used for processing of the one or more tasks 445 in order to manage the corresponding one or service requests 443 in accordance with the service data 477. It will be readily appreciated that, for example, excess capacity used by one or more task 445 can be measured in accordance with one or more mentoring and regulating techniques discussed above. In addition, the capacity management system 101 can be configured to determine the excess capacity needed to manage the one or more service requests 443 in accordance with the service data 477 that can be indicative of one or more service criteria. In a simple approach, virtually all of the excess capacity may be used for the duration needed to complete the one or more task 445.

However, in a more sophisticated approach, an estimation of excess capacity needed to manage the one or more service requests 443 in accordance with the service data 447 can be made so that excess capacity is provided only to the extent needed to complete a service request 442 in accordance with one or more service criteria.

It should be noted that an estimation of excess capacity needed may be revised based on the monitoring of the processing of the one or more tasks 445 which correspond to the one or more service requests 443. For example, one or more of the monitoring and regulation techniques described above can be used to determine the excess capacity needed to manage the one or more service requests 443 in accordance with the service data 477 in a dynamic manner, and possibly in a “closed-loop” capacity management system where the system can automatically determine the excess capacity needed and adjust the excess capacity as needed to meet service criteria.

To further elaborate FIG. 14A depicts a method 450 for managing one or more services of a database or database system in accordance with one embodiment of the invention. The database or database system can include one or more database nodes operable to process data stored for a database. In addition, the database or database system can be operable at a configured capacity which is below its full capacity to serve the one or more services. Method 450 can, for example, be performed by the capacity management system 101 depicted in FIG. 13.

Referring to FIG. 14A, initially, it is determined (452) whether to use excess capacity available to the database or database system to serve one or more services of the database or database system. Generally, this determination (452) can be made based on one or more service criteria. As such, the determination (452) can, for example, be made based on one or more service levels, service definitions, service requirements, or service objectives (e.g., SLAs, SLGs). Accordingly, if it is determined (452) to use excess capacity available to the database or database system to serve one or more services of the database or database system, excess capacity can be used (454) to serve or service the one or more services of the database or database system in accordance with one or more service criteria. Thereafter, the method 450 can end. However, if it is determined (452) not to use excess capacity available to the database or database system, method 450 can end without allowing excess capacity to be used to serve the one or more services of the database or database system.

To elaborate even elaborate, FIG. 14B depicts a method 460 for managing one or more services of a database or database system in accordance with another embodiment of the invention. The database or database system can include one or more database nodes operable to process data stored in a database. In addition, the database or database system can be operable at a configured capacity which is below its full capacity to serve the one or more services. Method 460 can, for example, be performed by the capacity management system 101 depicted in FIG. 13.

Referring to FIG. 14B, initially, it is determined (462) whether one or more service requests (e.g., database requests or query) have been received. In effect, method 460 can wait to receive a service request for processing by the database system. If it is determined (462) that one or more service requests have been received, it is determined (464) whether there is service data associated with the one or more service requests that have been received. In other words, it can be determined (464) whether the one or more service requests are to be processed in accordance with one or more service criteria (e.g., SLAs, SLGs). If it is determined (464) that one or more service requests are not to be processed in accordance with one or more service criteria, method 460 can end.

However, if it is determined (464) that one or more service requests are to be processed in accordance with one or more service criteria, service data indicative of one or more service criteria for processing the one or more service requests can be obtained (466). In addition, monitoring of one or more tasks corresponding to the one or more service requests can be initiated (468). Furthermore, it can be determined (470) whether to use excess capacity to effectively process the one or more service requests in accordance with the one or more service criteria. If it is determined (470) not to use excess capacity, the one or more tasks corresponding to the one or more service requests are not allowed to be processed using the excess capacity available to the database or database system. In other words, the one or more tasks are processed in accordance with the configured capacity of the database or database system. However, if it is determined (470) to use excess capacity to effectively process the one or more service requests in accordance with the one or more service criteria, excess capacity can be provided. In other words, the task(s) corresponding to the one or more service requests can be allowed (472) access to the excess capacity so that the one or more service requests can be processed in accordance with their service criteria (e.g., SLA, SLG).

It should be noted that excess capacity provided and/or used can be measured for various applications, including, for example, billing and accounting. As such, optionally, it can be determined (474) whether to measure excess capacity provided and/or used to effectively process the service request(s) in accordance with their service criteria. As a result, excess capacity provided and/or used can be measured (476).

Furthermore, the one or more tasks corresponding to the service request(s) can be effectively monitored until it is determined (478) that their corresponding task(s) have completed and the service request(s) have been serviced before the method 460 ends. In accordance with the service method 460, excess capacity can be provided in a dynamic manner while the service request(s) is being processed. Also, the extent to which excess capacity is provided can be adjusted to meet service criteria in a dynamic manner while the service request(s) is being processed. This means that excess capacity or additional excess capacity can be effectively provided (472) during the processing of the one or more tasks corresponding to the service requests to ensure compliance with one or more service criteria. For example, if it is determined based on monitoring of processing of a task that a SLA cannot be met, excess capacity or additional excess capacity can be provided to process the task(s) in accordance with the method 460. Method 460 can end when it is determined (478) that the processing of the one or more tasks and consequently the processing of the one or more service requests have completed in accordance with their service criteria.

As noted above, excess capacity provided and/or used to process service requests in accordance with service criteria can be measured. It should be noted that all excess or additional CPU and I/O usage can be logged in the Database Query Log for easy reporting purposes. It should also be noted that in a SLG-Responsive priority management, enough resources can be given in order to meet a request's SLG, relinquishing the rest of the resources to other requests. If it is determined that the SLGs cannot be met, an SLG-Responsive priority management sub-system can utilize the excess capacity (using PM COD) on the database machine to meet the level of associated SLG.

In a deterministic priority scheme, however, an SLG may be un-necessary. Instead, requests can be associated with workloads that in turn can be associated with a general level of resource allocation dictating how much resources each individual request gets relative to requests at a different level of resource allocation. However, it will be appreciated that the techniques of the invention can be provided in a COD environment, where both deterministic priority and SLG-Responsive priority management schemes are utilized. This can, for example, be accomplished by defining each workload to have one or more of (i) a Real-Time Attribute with a corresponding Service Level Goal, and (ii) a “pecking order.” In other words, Real-Time workloads can allocate excess or additional resources, beyond the configured capacity of a system, from a PM COD sub-system resources, if necessary, to meet their Service Level Goals in accordance with one embodiment of the invention. Virtually, any number of pecking orders can be used in accordance with this embodiment. However, in the overall prioritization of the workloads, all real-time workload pecking-orders can fall ahead of all time-share workload deterministic levels. Further, multiple workloads can be assigned the same pecking order or deterministic level.

To elaborate further, FIG. 15 depicts an exemplary priority management scheme in accordance with one embodiment of the invention. Referring to FIG. 15, two (2) real-time workload pecking-orders are depicted which can use excess capacity to meet their service goals, where the remaining resources are divided up deterministically between a number of workloads in a Time-share basis.

In view of the forgoing, those skilled in the art will readily appreciate that a PM COD environment can, for example, be provided in at least in part, or entirely, by a Priority Scheduler, a Regulator and/or an Optimizer component to manage the excess capacity of the system in a dynamic and/or automatic manner in a “closed-loop” system in accordance with the techniques of the invention. In addition, fine grain control of excess capacity (e.g., excess CPU power) can be provided as needed to meet a SLG-responsive Workload Definition(s) (WDs) pursuant a SLG. Excess capacity provided at fine granules, for example, to meet a SLA or pursuant to a SLG, can also be measured and billed at a desired level granularity.

Additional techniques related to controlling the capacity of a database system are further discussed in the following two (2) U.S. Patent Applications which are both hereby incorporated by reference herein for all purposes: (i) U.S. patent application Ser. No. 13/250,150 entitled: “Managing excess capacity of database systems in a capacity controlled computing environment,” by LOUIS BURGER et al., (ii) U.S. patent application Ser. No. 13/250,006 entitled: “Managing capacity of computing environments and system that include a database,” by John Mark Morris et al.

The various aspects, features, embodiments or implementations of the invention described above can be used alone or in various combinations. The many features and advantages of the present invention are apparent from the written description and, thus, it is intended by the appended claims to cover all such features and advantages of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, the invention should not be limited to the exact construction and operation as illustrated and described. Hence, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention. 

What is claimed is:
 1. A computer-implemented method of controlling capacity of a database system that includes one or more database nodes operable to process data stored in a database managed by the database system, wherein each one of the database nodes includes at least one physical processor and non-transitory computer readable storage medium configured to be accessed by the at least one processor, wherein the at least one physical processor is further configured to use one or more resources of the database system in connection with the processing of the data stored in the database, and wherein the computer-implemented method comprising: obtaining, by at least one physical processor, a target capacity of the database system as a desired overall target capacity of the database determined at least partly based on a performance goal value of the database; effectively changing, by the at least one physical processor, from a current computing capacity to another computing capacity that is different than the current capacity to achieve the overall target capacity of the database system, by at least causing usage capacity of at least one of the resources to be changed, at least partly based on the target capacity, from a current usage capacity to another usage capacity different than the current usage capacity when the database system is operational and processing the data in the database, and wherein the causing of the usage capacity of the least one resource to be changed comprises: changing the capacity of at least one of the database nodes of the database system from a current capacity to a different capacity, by at least performing the following: changing the actual processing rate of one or more physical processors of the at least one of the database nodes of the database system from a current processing rate to a different processing rate to achieve the desired overall the target capacity of the database system, by at least skipping one or more clock cycles based on performance improvement recommendations monitored by a usage regulator; and effectively changing access capacity of at least one of the computing resources of the at least one of the database nodes of the database system from a current access capacity to a different access capacity to achieve the desired overall the target capacity of the database system.
 2. The computer-implemented method of claim 1, wherein the causing of the usage capacity of the least one resource to be changed comprises: causing the capacity of at least one resource to be changed dynamically at runtime.
 3. The computer-implemented method of claim 1, wherein the database system includes multiple database nodes operable to process data stored in the database and access at least one of the resources in parallel, and wherein the causing of the usage capacity of the least one resource to be changed comprises: causing capacity of first and second resources that can be accessed respectively by first and second nodes of the multiple nodes to be changed.
 4. The computer-implemented method of claim 3, wherein the causing of capacity of first and second resources to be changed is performed when the database is processing data, dynamically, at runtime.
 5. The computer-implemented method of claim 1, wherein the computer-implemented method further comprises: obtaining a target computing capacity of the database system, wherein the target computing capacity is the less than the full computing capacity of the database system; and wherein the causing of usage capacity of the least one resource to be changed cause the capacity of the at least one resource to be changed based on the target capacity.
 6. The computer-implemented method of claim 1, wherein the resources that can be accessed by one or more database nodes includes one or more of the following: one or more processors, one or more other computing resources, access to Input/Output (I/O) associated with the database, access to one or more operations, access to one or more database operations.
 7. The computer-implemented method of claim 1, wherein the limiting of the usage of least one the database nodes of the database system comprises: effectively delaying access to at least one of the computing resources, thereby delaying usage of the at least one computing resource.
 8. The computer-implemented method of claim 7, wherein the effectively delaying access to at least one of the computing resources comprises: scheduling access to the at least one computing resource according to a determined delay period.
 9. The computer-implemented method of claim 1, wherein the computer-implemmented method further comprises: obtaining monitored computing usage data by monitoring computing usage of one or more database nodes of the database system; and controlling the computing capacity of the database system based on the monitored computing usage data.
 10. The computer-implemented method of claim 1, wherein the limiting of the usage comprises: monitoring computing usage of at least a first activity that is not regulated with respect to its usage of at least one of the resources; determining, at least partially based on the monitored computing usage data, whether to regulate or change regulation of the computing usage of a second activity; and initiating regulation or changing the regulation of the computing usage of the second activity with respect to one or more of the resources when the determining determines to limit the computing usage of the second activity.
 11. The computer-implemented method of claim 1, where the computer-implemented method further comprises: obtaining a target computing capacity of the database system; and regulating the computing usage of one or more database activities associated with the database system based on the target computing capacity.
 12. The computer-implemented method of claim 1, wherein the computer-implemented method further comprises: monitoring the one or more database activities at least with respect to their usage of the one or more resources; regulating the computing usage of one or more database activities based on the monitoring of the one or more database activities when the database is active.
 13. The computer-implemented method of claim 1, wherein the computer-implemented method further comprises: determining, based on one or more criteria, whether to change capacity of the database system from the current computing capacity to the other computing capacity.
 14. The computer-implemented method of claim 1, wherein the one or more criteria comprises one or more of the following: managing a service of the database; managing a service level associated with a service of the database; and meeting a service level goal and/or service level agreement.
 15. The computer-implemented method of claim 1, wherein the computer-implemented method further comprises: determining that one or more service level goals and/or service level agreements would not be met at the current computing capacity; determining a second capacity of the database system that would allow the one or more service level goals and/or service level agreement to be met; and changing the computing capacity of the database system from the current computing capacity to a the second capacity.
 16. The computer-implemented method of claim 15, wherein the current computing capacity is a target and/or desired capacity of the database system, and wherein the computer-implemented method further comprises: changing back the computing capacity of the database system to the current capacity when the one or more service level goals and/or service level agreements have been met.
 17. The computer-implemented method of claim 15, wherein the computer-implemented method further comprises: allowing the excess capacity provided by changing to the second capacity to be used only of meeting the one or more service level goals and/or service level agreements.
 18. A system that includes one or more physical processors operable to: access one or more computing resources of a database system; control capacity of the database system below a full capacity of the database system, wherein the database system includes one or more database nodes operable to process data stored in a database, wherein each one of the one or more database nodes can use the one or more resources in connection with the processing of the data stored in the database; effectively changing capacity of the database system from a current computing capacity to another computing capacity of the database system that is different than the current capacity, by causing usage capacity of at least one of the resources to be changed from a current usage capacity to another usage capacity of the at least one resource, different than the current usage capacity; and wherein effectively changing capacity of the database system comprises the following: reducing the actual physical processing rate of the one more physical processors below their full processing rate at full computing capacity by at least skipping one or more clock cycles based on performance improvement recommendations monitored by a usage regulator; and effectively limiting access of the database system to at least one of the computing resources below an access level that can be achieved at full computing capacity of the at least one computing resource.
 19. A non-transitory computer readable storage medium that stores at least executable computer code that when executed controls capacity of a database system below its full capacity, wherein the database system includes one or more database nodes operable to process data stored in a database, wherein each one of the database nodes includes one or more physical processers, and wherein each one of the one or more database nodes can use one or more resources in connection with the processing of the data stored in the database, and wherein the non-transitory computer readable storage medium includes: executable computer code operable to effectively change capacity of the database system from a current computing capacity to another computing capacity that is different than the current computing capacity, by causing usage capacity of at least one of the resources to be changed from a current usage capacity to another usage capacity different than the current usage capacity, wherein effectively changing capacity of the database system comprises the following: reducing actual physical processing rate of one more physical processors below their full processing rate at full computing capacity by at least skipping one or more clock cycles based on performance improvement recommendations monitored by a usage regulator; and ffectively limiting access of the database system to at least one of the computing resources below an access level that can be achieved at full computing capacity of the at least one computing resource. 